Efficient treatment of uranium-containing wastewater by MXene/polyamine-amidoxime functionalized PAN composites

Uranium-containing wastewater poses severe threats to ecological safety and human health, yet the development of adsorbents with both high adsorption capacity and strong selectivity remains a critical challenge in environmental remediation. In this study, a novel composite material (MX/PAN-AO-PA) was constructed by combining amidoxime and polyamine bifunctionalized PAN (PAN-AO-PA) with MXene via solution-phase synthesis for efficient uranium wastewater treatment. This design integrates the 2D layered structure of MXene with the selective uranium-binding groups of PAN-AO-PA, which synergistically enhances the surface area and uranium affinity. At 313 K, pH = 6 and C 0 = 80 mg·L −1 , MX/PAN-AO-PA exhibited a maximum adsorption capacity of 609.49 mg·g −1 for U(VI), approximately 250 % higher than that of pristine MXene (171.6 mg·g −1 ) with excellent selectivity. The adsorption behavior follows the pseudo-second-order kinetic model and Langmuir isotherm model. After 5 adsorption-desorption cycles, the uranium removal rate remained over 80 %, demonstrating good cyclic stability. FTIR and XPS analyses confirm that the efficient adsorption of U(VI) stems from the synergistic coordination of amidoxime groups (C(=NOH)NH 2 ) and polyamine groups (−NH 2 ), as well as the chelating effect of oxygen-containing functional groups (-OH, O ) on the MXene surface. This composite holds significant application value in radioactive wastewater treatment. • MX/PAN-AO-PA firstly synthesized and used for U(VI) adsorption. • The actual adsorption of U(VI) by MX/PAN-AO-PA was 609.49 mg·g −1 . • The composite shows 250 % higher U(VI) adsorption than pristine MXene. • MX/PAN-AO-PA combines MXene with bifunctional PAN, enhancing sites and selectivity. • The composite maintains over 80 % U(VI) after 5 adsorption-desorption cycles.